Since 1994, the Mouse Genome Database (MGD) has provided the research community with essential online
information about the laboratory mouse. Primary areas of data coverage include maps and mapping data, gene
nomenclature and gene descriptions, strain polymorphisms and characteristics, and molecular reagents. In 1998, the Gene
Expression Database (GXD) went online, adding primary expression data to the system. GXD provides detailed
descriptions of expression assays, time-and space-specific expression results, original images, and extensive notes. We call
the combined resource MGI. Because of continuous data acquisition from a wide variety of sources, accurate and
comprehensive data integration, daily updates, and worldwide availability, MGI is a unique information resource for a
vitally important model organism.

In addition to continuous data updates, MGI regularly releases new features and enhancements to existing ones.
These features may include new types of data, links with additional online resources, more powerful query capabilities,
or improved access to existing features. Recent additions include a prototype mouse tumor database, a prototype of rat
genome data pages, links to additional databases including FlyBase, a gene quick-search facility, more direct links between
mouse markers and sequence entries, simplified site navigation design, a mouse facts page, and other items.

We will present a general overview of MGI's content and interface and review new features added in the past year.